Starbucks closed 8,000 company-owned US stores at around 2pm local time on Tuesday for anti-bias training of 175,000 employees after a high-profile incident in which two black men were arrested at one of its cafes when a manager called in police.

Some 6,000 licensed Starbucks cafes will remain open in locations such as grocery stores and airports, and those employees will be trained at a later time.

Starbucks Corp appealed to customers for forgiveness, saying its behaviour toward two black customers last month had been reprehensible.

On April 12, Philadelphia police arrested two men for trespassing after one had asked to use a restroom while awaiting a business meeting at the Starbucks. The men were told that restrooms were for customers only.

The company has settled privately with the men, and Starbucks has since announced that people can use its restrooms even if they are not buying anything.

Starbucks executive chairman Howard Schultz, the architect of the company’s move into a cafe format in the late 1980s, said in an open letter that the decision to call police and the men’s arrests “were reprehensible and did not represent the company’s mission and enduring values”.

“We determined that insufficient support and training, a company policy that defined customers as paying patrons – versus anyone who enters a store – and bias led to the decision to call the police,” he said.

The arrests sparked protests and accusations of racial profiling at the coffee chain known for its liberal stances on social issues such as same-sex marriage.

Black leaders who are advising Starbucks on the training hope it will reinvigorate decades-old efforts to ensure that minorities get equal treatment in restaurants and stores, setting an example for other corporations.

“The incident has prompted us to reflect more deeply on all forms of bias, the role of our stores in communities and our responsibility to ensure that nothing like this happens again at Starbucks,” Schultz said.

Analysts say Starbucks can ill afford the bad publicity at a time of growing competition in a coffee industry which has seen a number of rivals bought out or merged.

British sandwich and coffee shop chain Pret A Manger was sold for US$2 billion on Tuesday in the latest move by Germany’s billionaire Reimann family to challenge Nestle in the coffee sector.

Starbucks signed a US$7 billion licensing deal with Nestle earlier this month that banks on the power of its brand in the United States to strengthen the Swiss company’s leading position globally.